Cardiology
[ACLS IN A NUTSHELL]
Step 1: General Principles The Step 2 exam will ask to either identify the rhythm or choose an intervention. In order to identify the rhythm, follow these simple principles. 1 - Determine the rate: tachycardia is > 100, bradycardia < 60. 2 - Determine the QRS complex: wide is > .12msec and means it’s a ventricular rhythm while narrow is < .12msec and means it’s an atrial rhythm. These two things will give you 80% of your answers on the test. The third and final decision is if the rhythm is regular or irregular. Of course, to determine any of this an ECG, preferably a 12lead, is needed. With the ECG ask if there’s an arrhythmia or not. Note that there are two, maybe three, rhythms that are not arrhythmias. Normal Sinus Rhythm is what everyone should be in. Sinus tachycardia is typically a normal, physiologic response to an underlying stressor. Sinus bradycardia may be a normal rhythm in a competitive athlete, though they usually do not appear in a vignette or in the hospital as an “arrhythmia.” Step 2: Symptoms or No Symptoms Ask, “are there symptoms?” An arrhythmia without any symptoms does not warrant your attention. Simply: if there are no symptoms then you do nothing. “Nothing” means routine care: IV, O 2 , and Monitor. Likely, this will be a question about rhythm identification. Step 3: Stable vs Unstable If the patient has symptoms decide whether there’s time to stay and play or if definitive therapy is needed right now. Stability is a product of your own comfort. But for a test, if there’s chest pain, shortness of breath, altered mental status, or a systolic BP < 90, then the patient is considered unstable. If they’re unstable use electricity. If instead the patient has symptoms, but not any one of those listed above, the patient is stable. A patient who is stable has time to fix the rhythm. He/she isn’t going to die right now; pharmacotherapy can be used.
Normal Sinus Arrhythmia
S. Tach IVF O2 Monitor
Ø
Sxs
Stable SYS BP < 90 CP, SOB AMS
Any other symptoms Stable
Unstable
DRUGS Fast + Narrow – Adenosine Fast + Wide – Amiodarone Slow – Atropine
ELECTRICITY Fast – Shock Slow - Pace
Afib/Flutter RATE CONTROL βB, CCB
Tachy Rhythms Sinus Tachycardia Supraventricular Tachycardia Multifocal Atrial Tachycardia Afib Aflutter Vtach Vfib Torsades Brady Rhythms Sinus Bradycardia 1o Block 2o Block 3o Block Junctional Idioventricular
Atrial Narrow Ventricular Wide
Varying degree of PR intervals
Step 4: Choose an intervention If you’ve chosen unstable/electricity only one question needs to be asked - fast of slow. If the rhythm is fast + unstable then shock. If the rhythm is slow + unstable then pace. If you’ve chosen stable/electricity it’s a slightly more difficult task. For stable rhythms, there are three, maybe four, options. 1 If the rhythm is fast + narrow + stable use adenosine. 2 - If the rhythm’s fast + wide + stable use amiodarone. 3 - If the rhythm’s slow + stable use atropine (epi drips can also be used in the new ACLS roll out). 4 - If the rhythm’s Afib/Aflutter (note this is the only rhythm that actually had to be identified to do the right intervention), rate control is preferred. If he/she were unstable shock him/her since afib usually presents as a tachycardia. By “rate control” we mean Beta Blockers or Calcium Channel Blockers.
Intervention Pacer Cardioversion
Heart Rate Brady Tachy
QRS Complex Any Any
Stability Unstable Unstable
Atropine Adenosine Amiodarone Rate Control
Brady Tachy Tachy Tachy
Any Narrow Wide Afib/Flutter
Stable Stable Stable Stable
“Rate Control” = Verapamil / Diltiazem, Propanolol
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